The relation which one quantity or magnitude has to another of the same kind. It is expressed by the quotient of the division of the first by the second; thus, the ratio of 3 to 6 is expressed by / or /; of a to b by a/b; or (less commonly) the second term is made the dividend; as, a:b = b/a.
Hence, fixed relation of number, quantity, or degree; rate; proportion; as, the ratio of representation in Congress.
The spiral in a snail's shell is the same mathematically as the spiral in the Milky Way galaxy, and it's also the same mathematically as the spirals in our DNA. It's the same ratio that you'll find in very basic music that transcends cultures all over the world. Joseph Gordon-Levitt
The only true measure of success is the ratio between what we might have done and what we might have been on the one hand, and the thing we have made and the things we have made of ourselves on the other. H. G. Wells